During the automatic manufacture of certain types of electronic components, especially capacitors, the components are organized in a linear array on a disposable strip of chipboard or tagboard. These strips are an integral part of the capacitor manufacturing process. The strips are fed into a wire-forming machine. The machine cuts off lengths of wire from reeled stock, forms each length into a pair of "radial" capacitor leads, and deposits the leads at successive locations along the length of the strip. The leads are then fastened in place, usually by pressing a ribbon of adhesive tape thereover. During subsequent steps in the manufacture of the capacitors (such as insertion of a dielectric disk between the ends of the pair of leads), the strips serve as conveyors for the capacitors. Sprocket holes may be punched in the strips, and they are fed through the machinery by suitable sprocket drives. The following U.S. Pat. Nos. show capacitor producing machinery of the general type just described: Heibel, 2,766,501; Packman, 2,929,130; Weiss, 3,091,835; Dian, 3,215,168; and Masuzima, 4,192,061.
After the capacitors are finished, each strip is fed into an electrical testing device, which detects and removes any capacitors that are not acceptable from an electrical point of view. The output of the testing device is a strip having a gap at each place where a defective capacitor has been detected.
The capacitors must eventually be fed into an automatic insertion machine, which inserts them into printed circuit boards at the proper locations. But the strips which emerge from the testing machines are not suitable for direct input to the insertion machines. One reason for this is the presence of the gaps where the defective capacitors have been eliminated. Therefore the capacitors which pass their electrical test are removed from their old, gap-filled strip and remounted upon a new strip in consecutive order, i.e. without gaps. A machine which transfers capacitors from one strip to another and fastens them with a ribbon of adhesive tape is sometimes referred to as a "retaper".
In some cases there is also another reason for transferring or retaping the capacitors. Some capacitor-manufacturing machines mount the capacitors on short, discontinuous strips. But component insertion machines are designed to receive long, continuous strips wound upon reels. In addition to being short, the discontinuous strips are normally made of a thick chipboard material which would be too stiff to wind on reels even if the strips were longer. Thus a retaper transfers the capacitors from short, stiff chipboard strips to a much longer strip made of a more flexible material, such as tagboard, which is then wound upon a reel.
At least one retaper machine is known to be currently available on the world market. This prior art machine uses a plurality of successively operating puller devices to exert a frictional force on the heads of successive capacitors, thereby removing them from the chipboard strips. The design of these puller devices is such that the thickness dimension of the heads of the capacitors, and the distances from the capacitor heads to the edges of the chipboard strips, must both be within relatively tight tolerances. There is no provision for changing the puller devices to adapt to different types of capacitors. After being pulled from the old strips, the capacitors are allowed to drop in a relatively uncontrolled fashion upon the new strip, to which they are retaped. An indexing wheel is transversely grooved to engage the wire leads of the capacitors at one edge of the new strip. But at the other edge such engagement is not possible, because the ends of the wire leads are prematurely trimmed off where they overhang the tagboard strip. Moreover, the feeding of the ribbon of adhesive tape is not positively synchronized with the indexing wheel. After the new strip leaves the indexing wheel, the subsequent drive is purely frictional, even though sprocket drive holes are later punched in the strip for use after the strip leaves the retaping machine and is fed into the automatic insertion equipment. The machine also requires many different adjustments to accommodate itself to different capacitor sizes, and cannot be adjusted at all to accommodate different capacitor spacings on the old strips.